6/30 or 1/6 students earned at least a C. So basically you add up all of the students that earned different grades. 8+10+6+3+3. Which gives you 30. Then 5 people got a C so you put 5 over the total amount of students. 5/30. Lastly, you simplify to 1/6 by dividing by 5 on both sides.
